The invention relates to a method and a forming machine for working a workpiece, for example by deforming it or fixing it in another workpiece, in which the workpiece is fitted over a mandrel, at least a part of the mandrel is expanded so as to fix the workpiece, the workpiece and at least one tool, such as a forming roller, are rotated about an axis relative to each other and the workpiece is worked by means of said tool.
Expandable mandrels are known and they are e.g. locally provided with segments along their circumference, which segments can be moved outwards and inwards. When a workpiece is fixed in position on the mandrel, the segments are moved in outward direction until they engage the inner side of portions of the workpiece that are to be processed. Mandrels of this type are liable to relatively quick wear. In addition, it frequently happens that the workpiece can only be removed from the mandrel with difficulty.
For the sake of completeness it is noted that International patent application PCT/NL01/00939 (not pre-published) makes mention of an expandable mandrel.